Carbon fibers are manufactured from three precursor materials such as rayon polyacrylonitrile (PAN), and mesophase pitch. Due to low productivity of rayon-based CF, PAN and mesophase pitch have been more preferred. PAN has been most widely used materials for carbon fiber precursors for more than thirty years. Approximately 90% of CFs produced in the world is PAN-based CF. To produce CFs, three stages are required: wet spinning, stabilization, and carbonization. Stabilization of PAN is performed by heating from 200 to 300°C in air under tension, leading to cyclization, dehydrogenation, and oxidation. PAN molecules are cyclized to transform into a non-meltable ladder structure, which is critical to avoid melting during carbonization. For tensile testing, a single fiber was loaded to a paper tab and the tensile properties were determined using an Instron Universal Tester (Instron, USA) at 25°C.